Amidocuprates for Directed ortho Cupration: Structural Study, Mechanistic Investigation, and Chemical Requirements

Abstract

Gilman‐ und Lipshutz‐Amidocuprate wurden einer röntgenkristallographischen Analyse unterzogen, die darauf hindeutet, dass die Gegenwart von LiX (X=CN, I) und THF das Gleichgewicht zugunsten der Lipshutz‐Cuprate verschiebt und wichtig für die Erzeugung der aktiven Spezies in dirigierten ortho‐Cuprierungen ist. Dichtefunktionalrechnungen bescheinigen monomeren Gilman‐Cupraten eine beispiellos hohe Reaktivität (siehe Schema, DG=dirigierende Gruppe).

Structural Effects in Lithiocuprate Chemistry: The Elucidation of Reactive Pentametallic Complexes

“…[ 5 ] Recent advances have revealed so-called Gilman-type monomers and dimers[ 6 ] and (in line with theory)[ 7 ] heteroleptic monomers[ 8 ], [ 9 ] and dimers (Figure 1 a , b, d). [ 10 ] Conversely, cyanide-containing Lipshutz cuprates[ 11 ] with heteroaggregate structures have now been elucidated (Figure 1 e ),[ 3 ] with very recent work proving that the replacement of X=CN by X=halide affords structurally analogous complexes,[ 4c , d , 6 ] and suggesting use of the term Lipshutz-type to describe this wider group of comparable cuprates. Interestingly, although the reactivity of Lipshutz-type cuprates has been considered to often exceed that of their Gilman-type counterparts,[ 4b , 8 , 13 ] it was recently suggested that a Lipshutz-type reagent could be used to generate a more reactive Gilman-type intermediate in situ.…”

“…Structural organocuprate(I) chemistry was recently the subject of review. [ 5 ] Recent advances have revealed so-called Gilman-type monomers and dimers[ 6 ] and (in line with theory)[ 7 ] heteroleptic monomers[ 8 ], [ 9 ] and dimers (Figure 1 a , b, d). [ 10 ] Conversely, cyanide-containing Lipshutz cuprates[ 11 ] with heteroaggregate structures have now been elucidated (Figure 1 e ),[ 3 ] with very recent work proving that the replacement of X=CN by X=halide affords structurally analogous complexes,[ 4c , d , 6 ] and suggesting use of the term Lipshutz-type to describe this wider group of comparable cuprates.…”

“…Interestingly, although the reactivity of Lipshutz-type cuprates has been considered to often exceed that of their Gilman-type counterparts,[ 4b , 8 , 13 ] it was recently suggested that a Lipshutz-type reagent could be used to generate a more reactive Gilman-type intermediate in situ. [ 6 ]…”

“… Established lithium amidocuprate structure types; a) AM=N(CH 2 Ph)Et, R=Mes, n =3, S=THF;[ 9 ] AM=TMP, R=Ph, n =3, S=THF;[ 8 ] AM=TMP, R=Me, n =1, S=TMEDA;[ 8 ] b) AM=N(CH 2 Ph) 2 , R=Mes;[ 10 ] c) AM=X=NPh 2 , n =1, S=OEt 2 ;[ 12 ] d) AM=NHMes, AM′=NHPh, n =1, S=DME;[ 12 ] e) AM=TMP, X=CN, Cl, Br, I, n =1, S=THF. [ 3 , 4b – d , 6 ] …”

“…We have recently sought to develop our understanding of ligand and solvent influences on lithiocuprate structures by modifying our previous syntheses of [{(TMP) 2 Cu(X)Li 2 (thf)} 2 ] (X=CN,[ 3 ] halide[ 6 ]). To this end, TMPLi was added to CuCN before introducing Et 2 O.…”